Lasers are ubiquitous devices used for testing, measuring, printing, cutting, marking, medical applications, communications, data transmission, semiconductor processing, and a number of other applications. Many types of lasers have been developed to meet different performance criteria for different applications. Engraving, cutting, marking, printing, and many other applications require relatively compact lasers that generate high power outputs and have beams with a desired shape and energy distribution. Laser-based engraving and imaging systems, for example, are often used to engrave or otherwise form ornamental designs, such as text, logos, or other ornamental designs, on and/or in workpieces formed from various materials (e.g., plastics, wood, rubber, paper, etc.).
In some applications, the portions of the workpiece irradiated or otherwise affected by the laser can be filled or at least partially covered with ink, paint, and/or other suitable materials. Several different processes can be used to deposit ink or paint onto the workpiece. In some conventional applications, for example, the workpiece can be painted by hand. In other applications, a mask can be created that generally matches at least a portion of the logo or design on the workpiece. The ink or paint can then be applied to the workpiece using one or more spraying steps. If more than one color is required, several masking/spraying steps may be required.
In other applications, a material may need to be applied to a surface of the workpiece prior to irradiating the workpiece with the laser so that the laser energy can fuse the applied material to the workpiece or in some other way affect the applied material to mark the workpiece. Examples of this can include inks applied to circuit boards and subsequently fused to the surface by a laser beam to form a bar code or serial number, ceramic powders applied to metal materials and then fused to the surface by a laser beam, and UV-curable materials applied to the surface of a circuit board and then cured with a laser to form a mask before etching the unprotected areas of the circuit board in a chemical bath. Conventional methods for applying such materials generally include applying the materials manually by hand spraying or painting them onto the surface of the workpiece.
In still other applications, a material may need to be applied to a surface of the workpiece to aid in the marking or cutting process performed by the laser beam. Examples of this can include water applied to the surface of an acrylic or wooden material to prevent discoloration of the unmarked area adjacent to a marked area and slightly acidic or alkaline materials applied to the surface of a stone material to help discolor the stone when it is etched by the laser beam to provide more contrast between the marked and unmarked areas.
Conventional methods such as those described above for depositing materials onto a workpiece, however, include several drawbacks. Manually applying material onto the workpiece, for example, is very labor-intensive and can significantly reduce throughput of processed workpieces. Furthermore, in some applications it may not be suitable to manually apply a particular material onto the workpiece. The masking approach also includes several drawbacks. For example, masking and spraying the workpiece is also labor-intensive because it can require a series of additional process steps. Furthermore, forming the masks can be relatively expensive and require a significant amount of time. Accordingly, there is a need to improve the systems and methods for processing workpieces.